I have been kick boxing for 3 years and I'm about to grade for my blue belt, I'm going to pick up some muay Thai as well soon which is very similar but adding in elbows and more clinching. I also did 3 years of karate reaching second green belt around 10 or so years ago. I stopped karate because I went travelling so couldn't regularly visit the same gym to train.

I do it for a combination of reasons. It helps keep me fit although I do a lot of other sports / weight training that all play a role in overall cross training. It keeps me flexible which is more and more important as you get older and I like to fight. Coming into training and letting out some aggression on some pads whilst working up a good sweat is a great cathartic release from the stresses of day to day life. I also enjoy the sparring a lot, it helps hone your reflexes and I don't mind at all getting hit to condition yourself for that possibility. I'll hopefully be competing in some inter club / amateur fights soon which I can't wait for. You do also have some peace of mins that should you need to defend yourself in day to day life you are able to do that.

Karate was a lot more 'Zen' in that the school I trained with didn't do much sparring and was more concentrated on your technique and working through your katas. It builds up your body and technique as well as building up respect for your sensei and the other students you train with. It was a lot of fun and has given me a great basis with technique for moving onto kick boxing but I prefer kick boxing because it is a lot more aggressive. The training sessions are more intense physically and I want to spar and get hit etc, which isn't for everyone.

Every school will be different, even if they are teaching the same style of martial art, in the way they approach things. The way they teach and way they go about things but you will always find a good supportive group of people who aren't out to hurt you intentionally and are invested in you training well and hard and supporting you.

I wouldnt worry too much about your hearing, most things will be shouted at you and you can follow people around you if you get lost but I would recommend you give it a try if it is something you are interested in. If you go to a place where people aren't respecting each other, their respective levels and their well being then leave and find yourself a better gym because I know they are out there. If you find a good one you can be part of a great community whilst pursuing fitness as well as a great skill.

In terms of what you should do, that is down to personal choice. Maybe try a few different ones. Obviously some concentrate on one thing or another like judo is a lot of throwing, muay Thai a lot of striking etc, so try and figure out what you want from it and maybe try some classes to see if you like it! :)